Download L-2 heart sounds

HEART SOUNDS
Dr. Taj
• There are four heart sounds SI, S2, S3 & S4.
• Two heart sound are audible with stethoscope
S1 & S2 (Lub - Dub).
• S3 & S4 are not audible with stethoscope
Under normal conditions because they are low
frequency sounds.
• Ventricular Systole is between First and
second Heart sound.
• Ventricular diastole is between Second and
First heart sounds.
First heart sound (S1)
• It is produced due to the closure of
Atrioventricular valves (Mitral & Tricuspid)
• It occurs at the beginning of the systole
and sounds like LUB
• Frequency: 50-60 Htz
• Time: 0.15 sec
Second heart sound (S2)
• It is produced due to the closure of
Semilunar valves (Aortic & Pulmonary)
• It occurs at the end of the systole and
sounds like DUB
• Frequency:80-90 Htz
• Time: 0.12 sec
• It is short and sharp
Third heart sound (S3)
• It occurs at the beginning of middle third
of Diastole
• Cause of third heart sound – Rush of
blood from Atria to Ventricle during rapid
filling phase of Cardiac Cycle. It causes
vibration in the blood.
• Frequency: 20-30 Htz
• Time: 0.1 sec
Fourth heart sound (S4)
or Atrial Sound
• It occurs at the last one third of Diastole
(just before S1)
• Cause of Fourth heart sound – Due to Atrial
contraction which causes rapid flow of blood from Atria
to Ventricle and vibration in the blood.
• Frequency: < 20 Htz
Note:
• Third and Fourth heart sound are low pitched sounds
therefore not audible normally with stethoscope
• S3 may be heard in children and young adults but
usually pathological in old age
Heart valves - superior view
Function of papillary muscle & Chordae tendineae
AREAS OF AUSCULTATION
AREAS OF AUSCULTATION
The Events of the Cardiac Cycle
Heart Murmurs
• Murmurs are abnormal sounds produced
due to (usually) abnormal flow of blood
through abnormal heart valves eg.:
stenosis or incompetence.
WHAT YOU SHOULD KNOW
FROM THIS LECTURE?
• Functions of A-V vales & Semilunar
valves.
• Functions of papillary muscles.
• There are four heart sounds :
S1, S2, S3, & S4.
• Audible with stethoscope are only S1 & S2
(Lub / Dub)
• Use of stethoscope.
• Places to be auscultated on the chest for heart
sounds i.e. Aortic, pulmonary, Mitral &
tricuspid area.
• Position of the subject while auscultation.
• Recording of heart sound – Phonocardiogram.
• Relationship of heart sound with ECG.
• Splitting of second heart sound A2-P2.
• Listening of S3 & S4 in physiological &
pathological conditions
• Murmurs (abnormal heart sounds).
Relationship of heart sound with ECG
Relationship of heart sound with ECG
Splitting of second heart sound A2-P2.
• Physiologic splitting of the 2nd heart sound
occurs during deep inspiration when the
A2 component splits from the P2
component by more than 0.2 seconds.